A so-called “electronic mirror” which displays, on a display screen, an image that has been captured with a camera and which can be used as a mirror has been developed and some people propose that such a mirror be used as an application for a mobile telecommunications device (see Patent Document No. 1, for example). Also, as disclosed in Patent Document No. 2, if the position of the camera can be changed, then the user can also use it as a rear-view mirror. Thus, the electronic mirror can perform a different function from a normal mirror which just reflects light.
However, the electronic mirror cannot be used in exactly the same way as a normal mirror, which makes the user feel somewhat uncomfortable especially when the camera is not level with his or her eyes (i.e., his or her line of sight is not aligned with the camera), which is one of problems with the electronic mirror. Thus, to overcome such a problem, Patent Document No. 3 proposes a method for synthesizing together images which have been shot with a plurality of cameras. Patent Document No. 4 proposes a method in which an image capturing section is arranged right behind a display section, thereby turning ON and OFF the display and image capturing sections synchronously with each other. And Patent Document No. 5 proposes a mechanism for changing the position of the camera. Meanwhile, although it does not relate to the field of electronic mirrors, Patent Document No. 6 proposes a technique for aligning the line of sight with the position of an image by detecting the line of sight of a car driver and shifting the location where an image is displayed.